JoshHeaps.Net/JoshHeaps.Net/wwwroot/js/casino/holdem/money.js

// Shared money handling for every casino surface. Kept apart from the table's
// rendering so the quick-split calculator can pull it in without dragging the whole
// seat/chip UI along with it.
//
// Everything the dealer touches is money, and money is decimal, so every module used
// to carry its own `Math.round(x * 100) / 100`. That's one rounding rule written out
// sixteen times in six files, which is sixteen chances for one of them to drift.
// It lives here now, and the modules that do arithmetic call these instead.
const Money = {
    // Half a cent. Chip comparisons need a tolerance: a stack that lands on
    // 0.0000000001 after a split is empty as far as a dealer is concerned, and an
    // exact `> 0` would treat that player as still having chips to bet.
    EPSILON: 0.004,

    // All money maths goes through cents, so 0.1 + 0.2 never reaches a payout.
    toCents(amount) {
        return Math.round((Number(amount) || 0) * 100);
    },

    fromCents(cents) {
        return cents / 100;
    },

    round(amount) {
        return this.toCents(amount) / 100;
    },

    // Cents only when there are cents.
    //
    // A chip game deals in whole numbers nearly all the time, and a trailing ".00"
    // is two characters that say nothing — measured at ~22px, against the 64px a
    // seat puck has to show a stack in. "$1,250,000.00" doesn't fit and wraps;
    // "$1,250,000" does. Amounts that genuinely carry cents still show them, so a
    // 25c-blind game reads exactly as it did.
    format(amount) {
        const value = Number(amount) || 0;
        const hasCents = this.toCents(value) % 100 !== 0;
        return `$${value.toLocaleString(undefined, {
            minimumFractionDigits: hasCents ? 2 : 0,
            maximumFractionDigits: 2,
        })}`;
    },

    // The same amount for a spreadsheet rather than for a person: no currency symbol
    // and no thousands separators, because those are what make a column of money
    // import as text and refuse to add up.
    forSheet(amount) {
        return (this.toCents(amount) / 100).toFixed(2);
    },

    // The chips to actually push, for an amount.
    //
    // A payout figure is the answer to the arithmetic, not to the dealer's job: they
    // still have to work out that $132 is two blacks, a green, a red and two whites
    // while six people watch. The chip legend already knows the denominations.
    //
    // Largest first, which is greedy and therefore not optimal for an arbitrary set of
    // values — but poker chips are not arbitrary. Every real set is canonical (each
    // denomination divides the next: 1, 5, 25, 100, 500), and greedy is exactly optimal
    // on those. A dealer who invents a 3-and-7 chip set gets a valid answer that might
    // use one chip more than it had to.
    //
    // Anything the smallest chip can't make comes back as `remainder` rather than being
    // rounded away: a 50c share in a game whose smallest chip is a dollar is a real
    // problem for the dealer to solve, not a rounding error to hide.
    // The smallest chip the table has said it plays with, in cents. Zero when no
    // denominations are set, which means the tool has been told nothing about what
    // chips exist and shouldn't pretend otherwise.
    chipStepCents(legend) {
        const values = (legend || [])
            .map(chip => this.toCents(chip.value))
            .filter(cents => cents > 0);
        return values.length > 0 ? Math.min(...values) : 0;
    },

    // Rounds an amount up to something the table can actually build out of its chips.
    //
    // Up rather than down or nearest: these are bet sizes, and a pot-sized bet that
    // has been shaved is no longer a pot-sized bet. Rounding up also can't drop an
    // amount below a legal minimum, which rounding the other way can.
    upToChip(amount, legend) {
        const step = this.chipStepCents(legend);
        if (step <= 0) return this.round(amount);
        const cents = this.toCents(amount);
        if (cents <= 0) return this.round(amount);
        return this.fromCents(Math.ceil(cents / step) * step);
    },

    // And down, for money coming *out* of a pot rather than going into it.
    //
    // The rake is the one amount in this tool that leaves the table, so the direction
    // of the rounding is a decision about whose money it is. Down: a house that can't
    // make 40c out of its chips takes nothing rather than a dollar, and the players
    // keep the difference. Being wrong in the players' favour is the only way to be
    // wrong about this that nobody has to argue about.
    downToChip(amount, legend) {
        const step = this.chipStepCents(legend);
        if (step <= 0) return this.round(amount);
        const cents = this.toCents(amount);
        if (cents <= 0) return 0;
        return this.fromCents(Math.floor(cents / step) * step);
    },

    chipBreakdown(amount, legend) {
        let cents = this.toCents(amount);
        if (cents <= 0) return { chips: [], remainder: 0 };

        const values = (legend || [])
            .map(chip => ({ chip, cents: this.toCents(chip.value) }))
            .filter(entry => entry.cents > 0)
            .sort((a, b) => b.cents - a.cents);

        const chips = [];
        values.forEach(entry => {
            const count = Math.floor(cents / entry.cents);
            if (count <= 0) return;
            cents -= count * entry.cents;
            chips.push({ value: this.fromCents(entry.cents), count, color: entry.chip.color });
        });

        return { chips, remainder: this.fromCents(cents) };
    },

    // "2×$50, 1×$25, 2×$1" — the breakdown as a dealer would say it out loud.
    //
    // A table with no chip legend gets nothing rather than "$132 no chip covers": it
    // hasn't told us its denominations, so there is no advice to give and the amount
    // stands on its own. A legend that exists but can't reach the amount is different,
    // and does say so.
    formatChipBreakdown(amount, legend) {
        const hasDenominations = (legend || []).some(chip => this.toCents(chip.value) > 0);
        if (!hasDenominations) return "";

        const { chips, remainder } = this.chipBreakdown(amount, legend);
        if (chips.length === 0 && remainder === 0) return "";
        const parts = chips.map(chip => `${chip.count}×${this.format(chip.value)}`);
        if (remainder > 0) parts.push(`${this.format(remainder)} no chip covers`);
        return parts.join(", ");
    },

    // Should focusing this field select what's already in it?
    //
    // Every amount box in this tool opens pre-filled with a suggestion: the raise pad
    // offers the minimum, Add chips offers a buy-in, the seat editor offers the stack
    // it already has. A dealer taps the box because they want a *different* number,
    // and a tap puts the caret after the suggestion instead of over it. Measured on a
    // phone: the raise pad showing 4, tap, type "60" — the field reads 460. Add chips
    // showing 200, tap, type "50" — 20050.
    //
    // Only number boxes. A name or a note is a thing you edit, and selecting all of
    // it on focus would be the same mistake pointing the other way.
    selectsOnFocus(field) {
        if (!field || field.tagName !== "INPUT") return false;
        const type = String(field.type || "").toLowerCase();
        if (type === "number") return true;
        return type === "text" && String(field.inputMode || "").toLowerCase() === "decimal";
    },

    // "+$40.00" / "-$40.00" rather than "$-40.00" — a standings column is read at a
    // glance, and the sign belongs out front where the eye lands first.
    formatSigned(amount) {
        const value = Number(amount) || 0;
        if (value > 0) return `+${this.format(value)}`;
        if (value < 0) return `-${this.format(Math.abs(value))}`;
        return this.format(0);
    },
};

if (typeof module !== "undefined" && module.exports) {
    module.exports = Money;
}